Internal combustion engine with at least two exhaust gas turbochargers

Abstract

A cylinder-piston internal combustion engine which includes at least two single or two two-stage exhaust gas turbochargers which together and in parallel supply the cylinder of the internal combustion engine with charging air when there is a large supply of exhaust gases from the internal combustion engine. When there is a small amount of exhaust gases available, at least one of the exhaust gas turbochargers is adapted to be switched off so as to increase the charging pressure. A check valve is disposed in a suction line of a compressor of the exhaust gas turbocharger which is adapted to be switched off with the check valve allowing a flow of air in a suction line of the compressor in a direction of the compressor but prevents a flow of air in an opposite direction.

I claim: 
     
       1. A cylinder-piston internal combustion engine which includes two exhaust gas turbocharger means arranged in parallel for both supplying the cylinder of the internal combustion engine with charging air when there is a large supply of exhaust gases, each exhaust gas turbocharger means including an exhaust gas turbine for driving a charging air compressor means, and means for switching off at least one of the exhaust gas turbocharger means when only a small amount of exhaust gas is available so as to increase a pressure of the charging air, characterized in that a check valve means is disposed in a suction line of the compressor means of the exhaust gas turbocharger means which can be switched off for allowing a flow of air in the suction line in a direction of the compressor means but preventing a flow of air in an opposite direction, said check valve means being adapted to be automatically opened and closed by a suction effect of the compressor means of the exhaust gas turbocharger means which can be switched off, and in that means are provided for communicating the exhaust gas turbocharger means which can be switched off with the remaining exhaust gas turbocharger means so that a pressure produced by the compressor means of the remaining exhaust gas turbocharger means acts on both a pressure and suction side of the compressor means of the exhaust gas turbocharger means which can be switched off. 
     
     
       2. A cylinder-piston internal combustion engine according to claim 1, characterized in that means are provided for controlling a positioning of the check valve means so that the check valve means is held in an open position after a switching-in of the exhaust gas turbocharger means until just before a switching-off of the exhaust gas turbocharger means. 
     
     
       3. A cylinder-piston internal combustion engine according to one of claims 1 or 2, characterized in that an exhaust gas line means is provided for directing a flow of exhaust gases to both exhaust gas turbocharger means, the means for communicating the exhaust gas turbocharger means with the remaining exhaust gas turbocharger means includes charging air line means disposed between the respective compressor means of the exhaust gas turbocharger means and the cylinder of the internal combustion engine and a connecting conduit means for connecting the charging air line means with each other, and in that a combustion chamber means is arranged between the exhaust gas line means and the charging air line means for supplying additional exhaust gases to the exhaust gas line means. 
     
     
       4. A cylinder-piston internal combustion engine according to claim 3, characterized in that means are provided for controlling a quantity of charging air fed from the charging air line means to the combustion chamber means. 
     
     
       5. A cylinder-piston internal combustion engine according to claim 4, characterized in that the means for switching off the exhaust gas turbocharger means includes a controllable exhaust valve means disposed in the exhaust gas line means for selectively interrupting a flow of exhaust gases to the exhaust gas turbocharger means to be switched off. 
     
     
       6. A cylinder-piston internal combustion engine according to claim 5, characterized in that at least one charging air cooler means is disposed in the charging air line means between the compressor means and the cylinder of the internal combustion engine. 
     
     
       7. A cylinder-piston internal combustion engine according to one of claims 1 or 2, characterized in that each of the exhaust gas turbocharger means is constructed as a two-stage exhaust gas turbocharger which includes a high pressure exhaust gas turbine means for driving a high pressure compressor and a low pressure exhaust gas turbine means for driving a low pressure compressor. 
     
     
       8. A cylinder-piston internal combustion engine according to claim 7, characterized in that the means for switching off the exhaust gas turbocharger means includes a controllable exhaust valve means for selectively interrupting a flow of exhaust gases to the exhaust gas turbocharger means to be switched off. 
     
     
       9. A cylinder-piston internal combustion engine according to claim 8, characterized in that a charging air cooler means is arranged between an input side of the high pressure compressor means and an output side of the low pressure compressor means of each of the two-stage exhaust gas turbochargers, and in that a further common charging air cooler means is arranged at an output side of each of the high pressure compressor means of the respective two-stage exhaust gas turbochargers.